1. Field of the Invention
The present invention relates to a method and apparatus for performing a non-invasive measurement of a concentration of a body component. More specifically, the present invention relates to a non-invasive body component concentration measuring apparatus and method of noninvasively measuring a concentration of a body component using a difference absorption spectrum corresponding to a quantity of interstitial fluid varied by adjusting a thickness of a specific soft tissue of a sample.
2. Description of the Related Art
Presently, about 5% of the human population suffers from diabetes, and this percentage is increasing. Diabetes is a chronic disease for which there is no complete cure, and requires a lifetime of attention and/or treatment, including self care by a patient.
Self care requires that a diabetic himself must measure his blood glucose from blood collected from a fingertip two to five times a day using a home blood glucose meter. The diabetic then records the measured blood glucose in a diabetic diary, and must adjust intake of food, physical activity, and/or use of medication or insulin depending on the measured results. The recorded blood glucose can be maintained by the diabetic and provided to a doctor during medical treatment.
Unfortunately for diabetics, pain and infections may be caused by frequent collection of blood. Thus, daily measurement of blood glucose imposes a significant burden on a diabetic. Therefore, studies of measuring blood glucose without collecting blood have been conducted. For example, research has been conducted into applying harmless light onto a part of a human body and detecting the light having reacted with the human body to measure the blood glucose of the human body.
By means of near-infrared spectroscopy employing a multi-variation statistical analysis, glucose in complicated biological media or various reacting mixtures can be selectively analyzed, which is one of the above-mentioned studies. Nevertheless, the technology of extracting glucose data from near-infrared spectra non-invasively measured from the human body still has significant technical problems that remain to be solved.
More specifically, several research reports have reported successful measurements of blood glucose, but in these reports, signal-to-noise ratios of the spectra are low, specificity of the blood glucose is low, and reproducibility of the measured signals is low.
In order to solve the above problems, several conventional methods of measuring blood glucose through absorbance analysis using a glucose overtone band and a combination band in a near-infrared area to develop a bloodless blood glucose meter have been suggested. Each of these conventional methods, however, suffer from disadvantages such as significant estimation error due to variations in conditions during measurements, difficulty in estimating a concentration of glucose in particular, and difficulty regarding reproducibility.